A well known structure for mounting sheaves, sprockets, couplings, gears and similar machine elements onto shafts consists of a tapered bushing having a longitudinal slit extending the length thereof and a cylindrical bore therethrough, for gripping the shaft internally and seating on a corresponding tapered surface in the bore of the hub of the machine element. There are generally two types of tapered bushings which are extensively used for securing the machine elements to the shaft, one consisting of a tapered body of a frustoconical shape secured in the hub bore, normally by two screws seated in holes intersecting the interface of the bushing and hub and having screw threads in the portion thereof in the hub and having a plain surface in the portion in the bushing. The screws abut against the end of the hole portion in the bushing and, when the screw is tightened, the end of the screw forces the bushing into the tapered bore of the hub, thereby causing the bushing to contract around and grip the shaft and to seat firmly onto the tapered surface of the bore. When the bushing has been secured in place in the machine element, the ends thereof are normally substantially flush with the respective ends of the hub, as are the heads of the securing screws. The bushings are removed from the bores of the hubs by one or more jackscrews seating in holes similar to the securing holes, except that the screw threaded and plain portions are reversed with respect to the bushing and hub, and the abutment for the jackscrews is in the hub.
The other type of bushing is similar to the first one described above with respect to the tapered body, but instead of having the holes for the securing screws at the interface of the bushing and hub, the bushing has a radial annular flange disposed on the large end of the tapered body, usually containing three plain holes for receiving screws which extend through the flange into threaded holes in the end of the hub. The screws have heads thereon, and when the screws are tightened, they force the flange toward the end of the hub and the bushing body into the hub bore, thereby seating the tapered surface of the bushing on the tapered surface of the hub and contracting the bushing body onto the shaft. In the past, these two types of bushing were not interchangeable in the hubs of the various machine elements and hence, if both lines of bushing were to be made available to customers as on-the-shelf items, it was necessary to stock two lines of machine elements, such as sheaves, sprockets, couplings and gears, for the respective type of bushing. This not only increased the inventory of the various elements and parts for mounting them on the shafts, but also increased the fabricating, handling and storage costs.